For years, fans of the beloved "Harry Potter" franchise have flocked to Edinburgh, Scotland, to visit the sites where author J.K. Rowling had reportedly started writing the series.

But now, Rowling has revealed Edinburgh is actually not where the writing of the boy who lived began.

"I was renting a room in a flat over what was then a sports shop," Rowling said on Twitter, with an image of where she resided at the time of writing the first book. "The first bricks of Hogwarts were laid in a flat in Clapham Junction."

And fans were -- to borrow from the books -- were essentially petrified.

The news came after a fan posted a picture on Twitter of the Elephant House, a coffee shop in Edinburgh which on its website describes itself as the place "made famous as the place of inspiration to writers such as J.K. Rowling, who sat writing much of her early novels in the back room overlooking Edinburgh Castle."

The fan asked Rowling to explain "the truth about this 'birthplace' of Harry Potter."

Rowling, who is known to drop various bombshells and unknown tidbits about the franchise on Twitter, explained that the real "pen to paper" birth of Harry Potter himself, happened in her flat.

However, she said, the moment where she had the idea for the series itself was while she was riding on a train.

This is the true birthplace of Harry Potter, if you define 'birthplace' as the spot where I put pen to paper for the first time.* I was renting a room in a flat over what was then a sports shop. The first bricks of Hogwarts were laid in a flat in Clapham Junction. pic.twitter.com/HVORnPVboK